Solar heat supplies the gas pressure regulating and metering station (GPRMS) Braunshausen of EAM Netz GmbH in Hesse. The network operator had a 48 kW_th solar thermal system installed at the station to support the heating system. The solar heating system is characterised by its innovative and efficient design. The collector field consists of three different fields, each with different characteristics. A drainback collector array with a total area of 9.8 m² is located on the roof of the container. Another collector array is installed on a 2-axis tracker and covers a total area of 39.2 m². Both the drainback and tracker collector arrays are connected to a shared 3.8 m³ heat storage tank. There is also a collector array with a direct connection to the heating circuit of the station, with an area of 19.6 m².

The planned specific yield of the collectors is 640 kWh/m²/a (based on gross area), with the tracker making a particularly high contribution. Conventional heating is provided by a gas boiler and supplies the necessary gas preheating of approximately 16 K due to the pressure reduction from 43 to 10 bar. Before the solar thermal system was installed, gas consumption totalled 314 MWh/a.

The planned gas saving due to the solar thermal system is 49 MWh/a, which corresponds to a reduction of 13 tCO_2eq/a. In the future, a dew point control of the gas outlet temperature is also to be implemented to further reduce gas consumption. Theoretical calculations show that a gas saving of 30 % can be achieved by implementing a dew point control system alone.

This innovative solar thermal system in Braunhausen not only demonstrates the effective use of renewable heat, but also the ongoing optimisation of the GPRMS to further minimise primary energy consumption. The system was modernised as part of the research project “EffGas – Energetic optimization of gas pressure regulating stations (GPRMS) and development of measures in the German context” funded by the BMWK (Funding reference number: 03ET1522A). As a result, the system was equipped with adequate measurement equipment for a detailed evaluation.